Counseling | More and more young people are suffering from cancer. Can I reduce my risk?

Although rates of early-onset cancers are increasing for a variety of cancers, including breast, uterine, colorectal and prostate cancers, their incidence remains relatively low. In 2019, the global incidence rate of early-onset colorectal cancer was 5.7 cases per 100,000 people (up from 3.5 cases in 1990), and the incidence rate of breast cancer was 13.7 cases per 100,000 people (up from 9.6 cases in 1990) .

That’s why it’s critical to ask family members about their health history, which can influence when your doctor recommends your first mammogram or colonoscopy and whether you need more genetic testing. For example, about a quarter of patients with early-onset colorectal cancer have a family history and need to be screened before age 45, otherwise they will miss the opportunity to detect these cancers early and even prevent them.

When my patients ask why people get cancer, I often tell them to imagine a tower of blocks. Suppose it takes 100 blocks for a person to develop cancer. Heredity, environment and lifestyle habits can all contribute to this tower.

Some of us will inherit genetic mutations from our parents or be exposed to things in the womb that add obstacles to the tower before we even crawl. Some of us will grow up exposed to pollutants in the air, soil, or water; live in areas where ultra-processed foods are most plentiful and affordable for our families; or be infected with viruses that stimulate the development of cancer. None of it is a factor of our conscious choice.

Then, our age and a host of other exposures and risk factors (many of which scientists have yet to discover), including alcohol consumption, exposure to UV rays, smoking, and obesity, add more hurdles to the tower.

Behind the scenes, our immune systems are constantly scrambling to remove obstacles with varying success rates. No two people can achieve exactly the same 100 blocks in the same amount of time, and many people will never reach 100 blocks in their entire lives.

The factors that determine when and how someone develops cancer are unique, not always known, and often beyond an individual’s control. This is why some people who smoke never get cancer, while others who are in peak physical condition still get cancer.

One of the biggest challenges in dissecting the causes of early-onset cancer is that there is no single explanation, said Bilal Siddiqui, an assistant professor and medical oncologist at The University of Texas MD Anderson Cancer Center. There are many environmental factors, and we do not yet fully understand them all.

Why doesn’t the immune system fight cancer?

Cancers appear in all of us every day, but fortunately, they are usually detected and eliminated by our immune systems.

Several important factors that help cancer evade the immune system are regulated by the environment. Smoking, alcohol abuse and genetics are well-known risk factors. Other risk factors that were less common in previous generations may also explain the increase in cancer at younger ages.

Maternal obesity and high birth weight are associated with increased risk of colorectal cancer. Increases in sedentary behavior, such as watching television for long periods of time and drinking sugary drinks, all of which are associated with high fasting blood sugar and obesity, and are associated with earlier onset of cancer. Younger age at the onset of a woman’s first menstrual period, older age at the time of her first childbirth, and use of birth control pills all increase the risk of premenopausal breast cancer. Red meat consumption appears to play a detrimental role in early-onset colorectal cancer.

Siddiqui added that it’s important to remember that almost half of all cancers are preventable.

A study published in The Lancet in 2022 found that about 44% of cancer deaths are related to modifiable risk factors such as smoking or air pollution.

Exposures early in life that may cause cancer are difficult to study. Imagine being asked today to recall how many minutes you spent playing in the sun 15 years ago. But scientists are working on ways to overcome these barriers, such as scouring electronic health records for objective evidence and analyzing biological samples such as saliva and feces collected during childhood for clues.

What do I want my patients to know?

In addition to mitigating any known risk factors, we are better able to detect cancer earlier.

After knowing your family history, go get the screening test your doctor recommends. Less than 20% of people aged 45 to 49 are screened for colorectal cancer in a timely manner, and only about 66% of women aged 40 and older are screened for breast cancer.